JP4855996B2 - Mobile terminal and handover processing apparatus in wireless communication system - Google Patents

Description

  The present invention relates to a mobile radio terminal and a handover processing apparatus in a radio communication system. The present invention includes a mobile radio terminal (MS: Mobile Station) having a mobile function and a radio base station (BS: Base Station) that communicates directly with the MS, and performs handover for switching BSs that communicate with the movement of the MS. The present invention relates to a mobile communication system having a (HO: Handover) function.

  In a wireless communication system including a wireless base station (BS) that provides a wireless communication area and a mobile wireless terminal (MS), if the MS is within a range (service area) that can communicate with the BS by radio waves, And can communicate with other MSs and servers.

  In such a wireless communication system, generally, communication is interrupted when moving to an area where the radio waves of the BS with which the MS is communicating does not reach (that is, outside the service area of the BS). It has a handover (HO) processing function for switching BSs.

  During the above handover process, the link layer level connection between the MS and the BS is momentarily disconnected, and the MS cannot temporarily deliver the communication packet to the communication partner terminal. . A communication packet that the MS has attempted to transmit during the handover process is temporarily stored in a buffer memory inside the MS, and delivered to the communication partner after the handover process.

  In general, when communication is performed between terminals using TCP (Transmission Control Protocol), the time between the transmission of a packet and the response (ACK: Acknowledgement) to the packet is returned (RTT) between the terminal and the communication partner. : Round Trip Time) is measured, and a timeout value (RTO: Retransmission Time Out) of the data retransmission timer in the retransmission control is calculated based on this RTT. When ACK is not received even if it exceeds the current RTO value in a certain communication protocol (when a timeout occurs), congestion control works between terminals, and communication throughput between terminals decreases due to the slow start algorithm.

  For example, when the MS communicates with the communication partner using TCP in the wireless communication system, if the MS executes the handover process before returning the ACK to the communication partner, the ACK is the communication partner until the handover process is completed. In the meantime, the data retransmission timer of the communication partner may time out, and as a result, the communication throughput after the handover process is completed is reduced by the slow start algorithm.

Therefore, as a method for preventing a decrease in communication throughput after completion of handover processing due to ACK retention in the MS, a method is disclosed in which handover processing is executed after a packet with a notification window size of 0 is transmitted ( For example, refer nonpatent literature 1). According to this, before the handover process is executed, the MS transmits a packet with a notification window size of 0 to the communication partner, and by stopping the transmission of a new packet to the communication partner, the MS sends a new ACK. Since it becomes impossible to transmit, it is possible to prevent an ACK that has not been replied to the MS from remaining during execution of the subsequent handover process.
“Freeze-TCP: a True End-to-end TCP Enhancement Mechanism for Mobile Environment” in Proc. IEEE INFOCOMOO

  However, in the above-described method, when a packet is received from a communication partner by passing the packet with the notification window size set to 0, the MS needs to newly transmit an ACK, and depending on the execution timing of the handover process, There is a possibility that the handover process is executed before the ACK is returned, and as a result, there is a problem that the communication throughput after the completion of the handover process is lowered by the slow start algorithm.

  The present invention has been made in view of such problems, and a mobile radio terminal and a hand in a radio communication system capable of preventing a reduction in communication throughput after radio handover processing consisting of a mobile radio terminal and a radio base station. The object is to provide an over-processing device.

(1) The invention described in claim 1 includes a mobile radio terminal and a plurality of radio base stations that communicate with the mobile radio terminal by radio, and the communication between the mobile radio terminal and the communication counterpart terminal is performed for a certain period of time. A mobile radio terminal in a radio communication system for controlling a reduction in communication speed between the mobile radio terminal and a communication counterpart terminal when a reception response to transmission data is not received within the mobile station, in response to a request from the radio base station In response or autonomously determining the execution of the handover process to another radio base station, and when the execution of the handover process is determined by the handover determination means, the communication partner a reception response returning judging means for checking whether or not the return all received response for each data received from the terminal, the reception response return determining means When return of the received response is determined to be completed Te, characterized in that it comprises a handover execution unit configured to execute the handover processing.

  (2) In the invention according to claim 2, the reception response return determination means includes a DL reception response confirmation number storage unit for storing a response confirmation number of the reception response last transmitted to the communication counterpart terminal, and a communication counterpart terminal. A DL transmission sequence number storage unit that stores a transmission sequence number of transmission data received last, a response confirmation number stored in the DL reception response confirmation number storage unit, and a DL transmission sequence number storage unit It is characterized in that it is determined that the reception response has been returned by comparing the stored transmission sequence numbers.

(3) In the invention according to claim 3, when the mobile radio terminal determines the execution of the handover process by the handover determining means, the mobile radio terminal receives all reception responses for each data transmitted to the communication counterpart terminal. A reception response reception determination unit for checking whether or not the reception response reception determination unit determines that reception of the reception response is complete, and performs the handover process. To do.

(4) The invention according to claim 4 includes a mobile radio terminal and a plurality of radio base stations that communicate with the mobile radio terminal by radio, and the communication between the mobile radio terminal and the communication counterpart terminal is performed for a certain period of time. In a wireless communication system that controls a reduction in communication speed between the mobile wireless terminal and a communication partner terminal when a reception response to transmission data cannot be received within the wireless communication terminal, the mobile wireless terminal responds to a request from the wireless base station. Or autonomously determining whether to execute a handover process to another radio base station, it is determined whether or not all reception responses for each data received from the communication partner terminal have been transmitted to the communication partner terminal. The handover process is executed when it is determined that all reception responses have been transmitted .

  (5) The invention according to claim 5 compares the transmission sequence number of the transmission data last received by the mobile radio terminal from the communication counterpart terminal and the response confirmation number of the reception response last returned to the communication counterpart terminal. Then, it is determined whether or not all reception responses have been returned.

  6). Also, in the present invention, when the mobile radio terminal determines to execute a handover process to another radio base station in response to a request from the radio base station or autonomously, all reception responses are received from the communication counterpart terminal. The handover process is executed when it is determined whether or not all reception responses have been received.

  7). In the present invention, the mobile radio terminal compares all the transmission responses by comparing the transmission sequence number of the transmission data last transmitted to the communication counterpart terminal with the response confirmation number of the reception response last received from the communication counterpart terminal. It is characterized by determining whether it has been received or not.

  8). Also, in the present invention, after the mobile radio terminal decides to execute the handover process, the condition information for the forced execution of the handover process is monitored, and when the conditions for the forced execution are satisfied, before the reception response is completely returned, Alternatively, the handover process is forcibly executed even before all reception responses are received.

  9. Further, in the present invention, the reception response reception determination means includes a UL response confirmation number storage unit for storing a response confirmation number of the reception response last received from the communication partner terminal, and a transmission of transmission data transmitted last to the communication partner terminal. A UL transmission sequence number storage unit for storing a trust sequence number, and comparing the response confirmation number stored in the UL response confirmation number storage unit with the transmission sequence number stored in the UL transmission sequence number storage unit To determine that reception of the reception response is completed.

  10. In the present invention, the mobile radio terminal stores a forced execution condition storage unit that stores information related to the forced execution condition of the handover process, and performs the forced execution of the handover process based on the information in the forced execution condition storage unit. A handover forcible execution determining unit for determining, and when the handover forcible execution determining unit determines to forcibly execute the handover process, the handover process is executed.

  (1) According to the first aspect of the present invention, when execution of the handover process is determined, it is checked whether or not the return of all reception responses is completed, and the return of all reception responses is completed. In this case, the handover process is executed, so that a reduction in communication throughput after the handover process can be prevented.

(2) According to the invention described in claim 2, it is possible to accurately grasp the return status of the reception response even when one reception response corresponds to the reception response of a plurality of transmission data.
(3) According to the invention described in claim 3, since all reception responses are received from the communication partner terminal before the handover process is executed, the data retransmission timer of the mobile radio terminal is prevented from timing out during the handover process. It is possible to prevent a decrease in communication throughput after completion of the handover process by the slow start algorithm.

  (4) According to the invention of claim 4, it is determined whether or not all reception responses have been returned to the communication partner terminal, and when it is determined that all reception responses have been returned, the handover process is executed. By doing so, it is possible to prevent a decrease in communication throughput after the handover process.

  (5) According to the invention described in claim 5, the mobile wireless terminal compares the transmission sequence number of the transmission data last received from the communication partner terminal with the response confirmation number of the reception response last returned to the communication counterpart terminal. By doing so, it can be determined whether or not all reception responses have been returned.

  6). Further, in the present invention, when the mobile radio terminal determines to execute a handover process to another radio base station in response to a request from the radio base station or autonomously, all reception responses are received from the communication counterpart terminal. , It is possible to prevent a decrease in communication throughput after the handover process by executing the handover process when it is determined that all reception responses have been received.

  7). In the present invention, the reception response reception completion determination means stores a UL response confirmation number storage for storing a response confirmation number of the reception response last received from the communication partner terminal, and transmission data transmitted last to the communication partner terminal. A UL transmission sequence number storage unit for storing the transmission sequence number of the transmission response number, and comparing the response confirmation number stored in the UL response confirmation number storage unit with the transmission sequence number stored in the UL transmission sequence number storage unit By determining that reception of the reception response is completed, the reception status of the reception response can be accurately grasped even when one reception response corresponds to the reception response of a plurality of transmission data. It becomes possible.

  8). Further, in the present invention, the mobile radio terminal stores a forced execution condition storage unit that stores information related to the forced execution condition of the handover process, and the forced execution of the handover process based on the information in the forced execution condition storage unit A handover forcible execution determination unit for determining the handover process, and when the handover forcible execution determination unit determines to forcibly execute the handover process, a single reception response is obtained by executing the handover process. Even in the case of dealing with a plurality of transmission data reception responses, it is possible to accurately grasp the reception status of the reception responses.

  9. In the present invention, the reception response reception completion determination means stores a UL response confirmation number storage for storing a response confirmation number of the reception response last received from the communication partner terminal, and transmission data transmitted last to the communication partner terminal. A UL transmission sequence number storage unit for storing the transmission sequence number of the transmission response number, and comparing the response confirmation number stored in the UL response confirmation number storage unit with the transmission sequence number stored in the UL transmission sequence number storage unit By determining that reception of the reception response is completed, the reception status of the reception response can be accurately grasped even when one reception response corresponds to the reception response of a plurality of transmission data. It becomes possible.

  10. Further, in the present invention, the mobile radio terminal stores a forced execution condition storage unit that stores information related to the forced execution condition of the handover process, and the forced execution of the handover process based on the information in the forced execution condition storage unit A handover forcible execution determination unit for determining the handover process, and when the handover forcible execution determination unit determines to forcibly execute the handover process, a single reception response is obtained by executing the handover process. Even in the case of dealing with a plurality of transmission data reception responses, it is possible to accurately grasp the reception status of the reception responses.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a principle block diagram of the present invention. In the figure, 20 is a mobile radio terminal (MS). In the mobile radio terminal 20, 1 collects information on conditions for executing the handover process, and a handover determination unit that determines execution of the handover process. 2 returns all reception responses to the data received from the communication partner terminal. The reception response return determination unit notifies the handover execution unit of completion of reception response return when it is determined whether or not all reception responses are returned.

  3 determines whether or not all the reception responses to the data transmitted to the communication partner terminal have been received. When it is determined that all the reception responses have been received, the handover execution unit is notified of the reception response reception completion. The reception response reception determination unit 4 executes a handover process upon receiving a notification from the reception response return determination unit 2 and the reception response reception determination unit 3 or a handover process execution notification from the handover forced execution determination unit The handover execution unit 5 is a forced execution condition storage unit that stores conditions for forcibly executing the handover process.

6 collects information on conditions for forced execution of the handover process, determines the forced execution of the handover process, and notifies the handover execution unit 4 of the execution of the handover process when the forced execution of the handover process is determined. An over-forced execution determination unit, 7 is a DL transmission sequence number storage unit for storing a transmission sequence number of transmission data last received from a communication partner terminal, and 8 is a response confirmation number of a reception response last returned to the communication partner terminal. A DL reception response confirmation number storage unit for storing, a UL transmission sequence number storage unit for storing a transmission sequence number of transmission data last transmitted to the communication partner terminal, and 10 a reception response received last from the communication partner terminal This is a UL response confirmation number storage unit for storing the response confirmation number. An outline of the operation of the mobile radio terminal configured as described above is as follows.
(Regarding the first embodiment)
The handover determining unit 1 collects information on conditions for executing the handover process regularly or irregularly, and monitors whether or not the handover process should be executed based on the collected information. When it is determined that the handover process should be executed as a result of monitoring, the reception response / return determination unit 2 is requested to perform the determination process. The reception response return determination unit 2 monitors the return status of the reception response with respect to the data received from the communication partner terminal, and when determining that all the reception responses have been returned, notifies the handover execution unit 4 to that effect. When the handover execution unit 4 receives a notification from the reception response return determination unit 2, the handover execution unit 4 executes a handover process.

As a result, all reception responses are returned before the handover process is executed, so that the reception response does not stay in the mobile radio terminal during the handover process, and the data retransmission timer of the communication partner can be prevented from timing out. In addition, it is possible to prevent a decrease in communication throughput after completion of the handover process by the slow start algorithm.
(Regarding the second embodiment)
The DL transmission sequence number storage unit 7 monitors transmission data received from the communication partner terminal, and stores a transmission sequence number assigned to the transmission data. The DL reception response confirmation number storage unit 8 monitors the reception response returned to the communication partner terminal, and stores the response confirmation number given to the reception response. The reception response return determination unit 2 obtains the transmission sequence number stored in the DL transmission sequence number storage unit 7 and the response confirmation number stored in the DL reception response confirmation number storage unit 8 and their values. It is possible to determine whether or not all received responses have been returned.

Thereby, even when one reception response corresponds to the reception response of a plurality of transmission data, it is possible to accurately grasp the return status of the reception response.
(Regarding the third embodiment)
When the handover determination unit 1 determines that the handover process should be executed, the handover determination unit 1 can request the reception response reception determination unit 3 in addition to the reception response return determination unit 2 to perform the determination process. The reception response reception determination unit 3 monitors the reception status of the reception response for the data transmitted to the communication partner terminal, and when determining that all the reception responses have been received, notifies the handover execution unit 4 to that effect. When the handover execution unit 4 receives a notification from the reception response return determination unit 2 and the reception response reception determination unit 3, the handover execution unit 4 executes a handover process.

Accordingly, since all reception responses are received from the communication partner terminal before the handover process is executed, it is possible to prevent the data retransmission timer of the MS from timing out after the handover process, and the handover process using the slow start algorithm It is possible to prevent a decrease in communication throughput after completion.
(Regarding the fourth embodiment)
The UL transmission sequence number storage unit 9 monitors transmission data transmitted to the communication partner terminal, and stores a transmission sequence number assigned to the transmission data. The UL reception confirmation number storage unit 10 monitors the reception response received from the communication partner terminal, and stores the response confirmation number given to the reception response. The reception response reception determination unit 3 acquires the transmission sequence number stored in the UL transmission sequence number storage unit 9 and the response confirmation number stored in the UL reception response confirmation number storage unit 10, and both values It is possible to determine whether or not all the reception responses have been returned.

Thereby, even when one reception response corresponds to the reception response of a plurality of transmission data, it is possible to accurately grasp the reception status of the reception response.
(Regarding the fifth embodiment)
The handover forcible execution determination unit 6 collects information on conditions for forced execution of the handover process regularly or irregularly, and monitors whether the handover process should be forcibly executed based on the collected information. As a result of monitoring, when it is determined that the handover process should be forcibly executed, the handover execution unit 4 is notified of this. When the handover execution unit 4 receives a notification from the handover forced execution determination unit 6, the handover execution unit 4 executes a handover process.

  As a result, even if the mobile radio terminal is in a state of waiting for receiving or returning a reception response, the handover process can be executed if the condition for forced execution is satisfied. It is possible to avoid a situation in which communication with the base station is interrupted.

  Next, examples of the present invention will be described. FIG. 2 is a diagram showing a system configuration example to which the present invention is applied. The same components as those in FIG. 1 are denoted by the same reference numerals. The figure comprises a mobile radio terminal (MS) 20, BS # 1, BS # 2 of two radio base stations (BS) 30, and a server 40 located on a network 35 reachable from both base stations. Communicates with the server 40 using the TCP via the base station BS # 1 while moving, and constantly monitors the received signal strength (RSSI: Receive Signal Strength Indicator) from the BS # 1 to detect signal noise relative to the received signal strength. This shows a system that communicates with the server 40 by switching the base station to communicate with when the ratio (CINR: Carrior Interface + Noise Ratio) becomes smaller.

  FIG. 3 is a block diagram showing an embodiment of a mobile radio terminal according to the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals. 21 measures the RSSI value and the noise component from the BS periodically or irregularly to calculate the CINR value, and the CINR measuring unit that notifies the handover determination unit 1 of the calculated result, 1 communicates from the CINR measuring unit 21 The CINR value of the BS being received is received, it is determined whether or not the acquired CINR value satisfies the condition held in the handover execution condition storage unit 22 or the handover forced execution condition storage unit 23, and the handover execution condition When the conditions held in the storage unit 22 are satisfied, the processing request is notified to the reception response return determination unit 2, the reception response reception determination unit 3, the DL control unit 24, and the UL control unit 25, and the handover is forcibly executed. This is a handover determination unit that notifies the handover execution unit 4 of a processing request when the conditions held in the condition storage unit 23 are satisfied.

  A handover execution condition storage unit 22 stores conditions for executing a handover process while checking reception or return status of a reception response. FIG. 4 shows an example of conditions stored in the handover execution condition storage unit 22. In the example shown in this figure, when the CINR value becomes smaller than 20 dB, the handover process is executed while checking the reception or return status of the reception response. Reference numeral 23 denotes a handover forced execution condition storage unit that stores conditions for forcibly executing the handover process. FIG. 5 shows an example of the conditions stored in the handover forced execution condition storage unit 23. In the example shown in FIG. 5, when the CINR value becomes smaller than 12.5 dB, the handover process is forcibly executed.

  2 receives a processing request from the handover determining unit 1 and determines whether or not a reception response is returned for all received data from the data reception status from the communication partner and the reception response return status for the data. It is a reception response return determination unit for determining. If there is a DL transmission sequence number storage unit 7 and a DL reception response confirmation number storage unit 8, information stored in them may be used in the determination. When all the reception responses are returned, the reception response return determination unit 2 notifies the handover execution unit 4 of the processing request.

  3 receives a processing request from the handover determining unit 1 and determines whether or not reception responses have been received for all transmission data from the data transmission status to the communication partner and the reception response reception status for the data. A reception response reception determination unit. When there is the UL transmission sequence number storage unit 9 and the UL reception response confirmation number storage unit 10, the information stored in them may be used in the determination. When all the reception responses are received, the reception response reception determination unit 3 notifies the handover execution unit 4 of the processing request.

  Reference numeral 7 denotes a DL transmission sequence number storage unit that holds a sequence number of data received from a communication partner. FIG. 6 shows an example of sequence numbers stored in the DL transmission sequence number storage unit 7. In the example shown in the figure, data having a sequence number of 100 is received.

  Reference numeral 8 denotes a DL reception response confirmation number storage unit that holds a reception response number of a reception response returned for data received from a communication partner. FIG. 6 shows an example of a sequence number stored in the DL reception response confirmation number confirmation unit 8. In the example shown in the figure, a reception response with a response number of 100 is returned. Reference numeral 9 denotes a UL transmission sequence number storage unit that holds a sequence number of data transmitted to a communication partner. FIG. 7 shows an example of the sequence numbers stored in the UL transmission sequence number storage unit 9. In the example shown in the figure, data having a sequence number of 500 is transmitted.

  Reference numeral 10 denotes a UL reception response confirmation number storage unit that holds a reception response number of a reception response (ACK) received for data transmitted to a communication partner. FIG. 7 shows an example of sequence numbers stored in the DL reception response confirmation number storage unit. In the example shown in FIG. 7, a reception response with a response number of 500 is returned. 4 receives a processing request from the reception response return determination unit 2, the reception response reception determination unit 3, or the handover determination unit 1, and executes a handover process. When the handover process is completed, the DL control unit 24 and the UL It is a handover execution unit that notifies the control unit 25 of a processing request.

  In addition to receiving data transmitted from the communication partner from the network 35 (see FIG. 2) and delivering the data to the OS 41, 26 receives transmission data for the communication partner from the data analysis unit 27 and transmits it to the network 35. It is a transmission / reception unit. 27 monitors the Up Link / Down Link data with the communication partner, and counts the number of data and reception responses transmitted to the communication partner, data received from the communication partner and reception responses, This is a data analysis unit that notifies the reception response return determination unit 2 and the reception response reception determination unit 3 of individual count numbers as reception response reception (return) determination information.

  FIG. 8 shows an example of the count value of each data counted by the data analysis unit 27. In the example shown in the figure, the number of data received from the communication partner (DL reception data number) is 2000, the reception response return number (DL reception response return number) is 2000, and the number of data transmitted to the communication partner (UL transmission data number). ) Is 1000, and the reception response reception number (UL reception response reception number) is 1000. Further, the transmission / reception data sequence number and response confirmation number may be used as reception response reception (return) determination information.

  Reference numeral 41 denotes an OS (operating system) that transfers data received from the transmission / reception unit 26 to an appropriate application, and receives data transmitted from the application to a communication partner from the application unit 42 and transfers it to the data analysis unit 27. Upon receiving a processing request from the handover determining unit 1, 24 transmits a packet with a notification window size of 0 to the communication partner to stop transmission of a new packet to the communication partner, and the handover execution unit 4 When receiving a processing request, the DL control unit transmits a packet having a notification window size of 1 or more to the communication partner and transmits the packet to the communication partner to resume transmission of a new packet.

Upon receiving a processing request from the handover determining unit 1, 42 accumulates data received from the application unit 42, stops data transmission (delivery to the data analyzing unit 27), and processes from the handover executing unit 4. When receiving the request, the UL control unit releases the accumulation of the data received from the application unit 42 and restarts the data transmission (delivery to the data analysis unit 27). Reference numeral 42 denotes an application unit that transfers data to be transmitted to the communication partner to the OS 41 and receives data received from the communication partner from the OS 41. The operation of the apparatus configured as described above will be described below.
(Embodiment 1)
At this time, for example, the CINR measurement unit 21, the handover determination unit 1, the handover execution condition storage unit 22, the reception response return determination unit 2, the handover execution unit 4, the data analysis unit 27, and the transmission / reception unit 26 The OS 41, the DL control unit 24, and the application unit 42. Next, the operation of each component will be described along the flow of processing.

  1. The handover execution condition storage unit 22 holds information about the conditions for executing the handover process in advance. As a setting means, for example, the administrator may set by a command, or information may be set by regular or irregular notification from the BS 30 (see FIG. 2). Not specified). In this embodiment, for example, as shown in FIG. 4, when the CINR value becomes smaller than 20 dB, execution of the handover process is determined.

  Note that an MS to which the present invention is applied requires more time than a conventional MS to determine whether to execute a handover process until the actual handover process is executed (in order to wait for all received responses to be returned). . As a result, when the MS is moving at a high speed, the MS to which the present invention is applied as compared with the conventional MS may be disconnected from the BS between the execution decision of the handover process and the execution. Becomes higher. For this reason, it is necessary to consider that the threshold value for determining the execution of the handover process is set higher than in the prior art so that communication with the BS is not easily interrupted.

  2. The transmission / reception unit 26, the data analysis unit 27, the OS 41, and the application unit 42 perform data transmission / reception and reception response transmission / reception with a communication partner terminal at regular or irregular intervals in cooperation. The transmission / reception unit 26 acquires data and a reception response from the communication partner terminal from the network and passes them to the data analysis unit 27. The data analysis unit 27 performs internal processing (details will be described later), and further passes the acquired data and reception response to the OS 41. The OS 41 transfers the data to an appropriate application and clears the data retransmission timer for the reception response. For Up Link, processing is performed in the reverse flow to that of downlink processing.

  3. In addition, the data analysis part 27 counts up the DL data reception number, when the data from a communicating party terminal are received from the transmission / reception part 26. FIG. When receiving a reception response to data from the communication partner terminal from the OS 41, the DL reception response return count is counted up. In this embodiment, for example, as shown in FIG. 8, the number of DL reception data is 2000, the number of DL reception response returns is 2000, and all reception responses for the reception data are returned.

  4). The CINR measurement unit 21 calculates the CINR value by measuring the RSSI value and noise component of the BS 30 at regular or irregular intervals. In the present embodiment, for example, the calculated CINR value is 15 dB. The CINR measurement unit 21 notifies the handover determination unit 1 of the CINR value 15 dB.

  5. The handover determining unit 1 compares the CINR value 15 dB with the execution determination threshold 20 dB held in the handover execution condition storage unit 22. In this case, since the measured value is lower than the threshold value and satisfies the condition for executing the handover process, the handover determining unit 1 determines the execution of the handover process, and the reception response return determining unit 2 and the DL The control unit 24 is notified of the processing request. If the conditions for executing the handover process are not satisfied, the handover determining unit 1 does nothing.

  6). When the DL control unit 24 receives a processing request from the handover determining unit 1, the DL control unit 24 creates a packet in which the notification window size addressed to the communication partner terminal is 0, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and stop data transmission from the communication partner terminal.

  The sixth process is not an essential process in the present invention. However, when an MS to which the present invention is applied in a real environment executes a handover, if data is transmitted without interruption from the communication partner terminal, there is always a state in which an unreturned receiving terminal remains in the MS. Since there is a possibility that the handover process cannot be executed, it is necessary to consider that data transmission from the communication partner terminal is stopped by some method. In the present invention, the method is not specified, but there is a method of transmitting a packet with a notification window size of 0 as shown in the present embodiment to the communication partner.

  7). When receiving the processing request from the handover determining unit 1, the reception response return determination unit 2 refers to the DL data reception number and DL reception response reply number of the data analysis unit 27, and receives a response to the reception data from the communication partner terminal Check if all the items are returned. In the present embodiment, as shown in FIG. 8, since the DL data reception number and the DL reception response return number are the same, the reception response return determination unit 2 determines that all reception responses have been returned, and the handover execution unit 4 is notified of the processing request. If the DL data reception number is larger than the DL reception response return number, it is determined that there is an unreturned reception response and waits until all reception responses are returned.

8). When receiving the processing request, the handover executing unit 4 executes the handover process. When the handover process is completed, the DL controller 24 is notified of the processing request.
9. Upon receiving a processing request from the handover execution unit 4, the DL control unit 24 creates a packet with a notification window size addressed to the communication partner terminal of 1 or more, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and resume data transmission from the communication partner terminal.

  According to this embodiment, when the execution of the handover process is determined, it is checked whether or not the return of all reception responses has been completed. Since the over process is executed, it is possible to prevent a decrease in communication throughput after the handover process.

  FIG. 9 shows a sequence diagram illustrating an example of the above-described operation. When receiving the data (S1), the transmission / reception unit 26 passes the data to the data analysis unit 27 (S2). Next, the data analysis unit 27 counts the number of received data (S3). When the number of received data is counted, the data analysis unit 27 delivers the received data to the OS 41 (S4). The OS 41 delivers the received data to the application unit 42 (S5). Next, the OS 41 delivers a reception response to the data analysis unit 27 (S6).

  The data analysis unit 27 counts the number of reception responses returned (S7), and delivers the reception response to the transmission / reception unit 26 (S8). The transmitting / receiving unit 26 transmits the received reception response to the communication partner terminal (S9).

  On the other hand, the CINR measurement unit 21 performs CINR measurement (S10), and notifies the handover determination unit 1 of the measurement value (S11). The handover determining unit 1 checks whether or not the measured value <threshold value (S12). When the measured value is smaller than the threshold value, a processing request notification is sent to the DL control unit 24 (S13). The DL control unit 24 creates a packet with a notification window size of 0 (S14) and passes it to the data analysis unit 27 (S15). The data analysis unit 27 delivers the packet to the transmission / reception unit 26 (S16), and the packet is transmitted from the transmission / reception unit 26 to the communication partner terminal (S17).

  If the measured value <threshold value, the handover determining unit 1 notifies the reception response / return determining unit 2 of the processing request (S18). The reception response return determination unit 2 refers to the DL reception response confirmation number storage unit 8 (S19), and checks whether the number of received data and the number of response returns are equal (S20). If they are equal, the handover execution unit 4 is notified of the processing request (S21), and the handover execution unit 4 performs the handover process (S22). When the handover process is executed, the handover execution unit 4 sends a processing request notification to the DL control unit 24 (S23). Next, the DL control unit 24 creates a packet having a notification window size of 1 or more (S24), and delivers it to the data analysis unit 27 (S25). The data analysis unit 27 transfers this to the transmission / reception unit 26 (S26), and the transmission / reception unit 26 transmits the transferred packet (S27).

According to this embodiment, since all reception responses are returned before the handover process is executed, the reception response does not stay in the wireless terminal during the handover process, and the data retransmission timer of the communication partner times out. It is possible to prevent a decrease in communication throughput after completion of the handover process by the slow start algorithm.
(Embodiment 2)
For the mobile radio terminal (MS) in this case, for example, the CINR measurement unit 21, the handover determination unit 1, the handover execution condition storage unit 22, the reception response return determination unit 2, and the DL transmission sequence number storage unit 7 A DL reception response confirmation number storage unit 8, a handover execution unit 4, a data analysis unit 27, a transmission / reception unit 26, an OS 41, a DL control unit 24, and an application unit 42. Next, the operation of each component will be described along the flow of processing.

  1. The handover execution condition storage unit 22 holds information about the conditions for executing the handover process in advance. As a setting means, for example, the administrator may set by a command, or information may be set by regular or irregular notification from the BS 30 (see FIG. 2). Not specified). In this embodiment, for example, as shown in FIG. 4, when the CINR value becomes smaller than 20 dB, execution of the handover process is determined.

  Note that an MS to which the present invention is applied requires more time than a conventional MS to determine whether to execute a handover process until the actual handover process is executed (in order to wait for all received responses to be returned). . As a result, when the MS is moving at a high speed, the MS to which the present invention is applied as compared with the conventional MS may be disconnected from the BS between the execution decision of the handover process and the execution. Becomes higher. For this reason, it is necessary to consider that the threshold value for determining the execution of the handover process is set higher than in the prior art so that communication with the BS is not easily interrupted.

  2. The transmission / reception unit 26, the data analysis unit 27, the OS 41, and the application unit 42 perform data transmission / reception and reception response transmission / reception with a communication partner terminal at regular or irregular intervals in cooperation. The transmission / reception unit 26 acquires data and a reception response from the communication partner terminal from the network and passes them to the data analysis unit 27. The data analysis unit 27 performs internal processing (details will be described later), and further passes the acquired data and reception response to the OS 41. The OS 41 transfers the data to an appropriate application and clears the data retransmission timer for the reception response. For Up Link, processing is performed in the reverse flow to that of downlink processing.

  3. In addition, when the data analysis unit 27 receives data from the communication partner terminal from the transmission / reception unit 26, the data analysis unit 27 analyzes the data packet, acquires the transmission sequence number of the TCP layer, and holds it in the DL transmission sequence number storage unit 7. When receiving a reception response to data from the communication partner terminal from the OS 41, the reception response packet is analyzed, a TCP layer response confirmation number is acquired, and held in the DL reception response confirmation number storage unit 8. In the present embodiment, for example, as shown in FIG. 6, it is assumed that the DL transmission sequence number is 100, the DL reception response confirmation number is 100, and there is an unreturned reception response in the MS.

  Here, the relationship between the transmission sequence number and the reception response number in TCP will be described. The TCP transmission sequence number is initialized when communication is established, and thereafter, the TCP transmission sequence number is increased by the number of transferred data bytes. For example, when the transmission sequence number of 20-byte data is 100, the transmission sequence number of data to be transmitted next is 100 + 20 = 120.

In addition, for the TCP reception response, the reception response confirmation number is set with a transmission sequence number to be sent next, and is sent back to the communication partner terminal. That is, in the above example, the reception response confirmation number of the response to the received data is 120. Therefore, the relationship between the sequence number for transmission of certain data and the reception response confirmation number of the reception response is as follows:
The transmission sequence number is smaller than the reception response confirmation number. In the example of the present embodiment, since the DL transmission sequence number (100) and the DL reception response confirmation number (100) are the same, the reception response for the data of the transmission sequence number 100 is not returned. I understand that there is.

  4). The CINR measurement unit 21 calculates the CINR value by measuring the RSSI value and noise component of the BS 30 at regular or irregular intervals. In the present embodiment, for example, the calculated CINR value is 15 dB. The CINR measurement unit 21 notifies the handover determination unit 1 of the CINR value 15 dB.

  5. The handover determining unit 1 compares the CINR value 15 dB with the execution determination threshold 20 dB held in the handover execution condition storage unit 22. In this case, since the measured value is lower than the threshold value and satisfies the condition for executing the handover process, the handover determining unit 1 determines the execution of the handover process, and the reception response return determining unit 2 and the DL The control unit 24 is notified of the processing request. If the conditions for executing the handover process are not satisfied, the handover determining unit 1 does nothing.

  6). When the DL control unit 24 receives a processing request from the handover determining unit 1, the DL control unit 24 creates a packet in which the notification window size addressed to the communication partner terminal is 0, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and stop data transmission from the communication partner terminal.

  7). Upon receipt of the processing request from the handover determination unit 1, the reception response return determination unit 2 receives the DL reception transmission sequence number and the DL reception from the DL transmission sequence number storage unit 7 and the DL reception response confirmation number storage unit 8, respectively. Get the response confirmation number for comparison. In the example of FIG. 6 of the present embodiment, since these values are the same, the reception response return determination unit 2 determines that there is still an unreturned reception response remaining in the MS, and returns the reception response. wait.

Thereafter, the DL transmission sequence number and the DL reception response confirmation number are monitored regularly or irregularly, and the relationship between the transmission sequence number and the reception response confirmation number is
When the transmission sequence number <the reception response confirmation number, the reception response return determination unit 2 determines that all reception responses have been returned, and notifies the handover execution unit 4 of the processing request.

8). When receiving the processing request, the handover executing unit 4 executes the handover process. When the handover process is completed, the DL controller 24 is notified of the processing request.
9. Upon receiving a processing request from the handover execution unit 4, the DL control unit 24 creates a packet with a notification window size addressed to the communication partner terminal of 1 or more, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and resume data transmission from the communication partner terminal.

According to this embodiment, even when one reception response corresponds to reception responses of a plurality of transmission data, it is possible to accurately grasp the return status of the reception response.
FIG. 10 is a sequence diagram showing an example of the operation of the present invention for explaining the above-described operation. When the transmission / reception unit 26 receives the data (S1), it passes it to the data analysis unit 27 (S2). The data analysis unit 27 stores the sequence number in the DL transmission sequence number storage unit 7 (S3). Further, the data analysis unit 27 delivers the received data to the OS 41 (S4). The OS 41 transfers the received data received to the application unit 42 (S5). Further, the OS 41 delivers a reception response to the data analysis unit 27 (S6). The data analysis unit 27 stores the response confirmation number in the DL reception response confirmation number storage unit 8 (S7). Further, the data analysis unit 27 delivers a reception response to the transmission / reception unit 26 (S8), and the transmission / reception unit 26 transmits the reception response to the communication partner terminal (S9).

  On the other hand, the CINR measurement unit 21 measures the RSSI value and noise component of the BS to calculate the CINR value (S10). Then, the calculated CINR value is notified to the handover determining unit 1 (S11). When the handover determining unit 1 receives the measured value of the CINR value, the handover determining unit 1 refers to the handover execution condition storage unit 22 (S12) and checks whether the measured value <threshold value (S13). If so, a processing request notification is sent to the DL control unit 24 (S14). Upon receiving this processing request notification, the DL control unit 24 creates a packet with a notification window size of 0 (S15), and delivers it to the data analysis unit 27 (S16). The data analysis unit 27 passes the packet to the transmission / reception unit 26 (S17), and the transmission / reception unit 26 transmits the packet to the communication partner terminal (S18).

  Further, when the measured value <threshold value, the handover determining unit 1 notifies the reception response / return determining unit 2 of the processing request (S19). The reception response return determination unit 2 accesses the UL reception response confirmation number storage unit 10 to refer to the response confirmation number (S20), and accesses the UL transmission sequence number storage unit 9 to refer to the transmission sequence number ( S21). Next, the reception response return determination unit 2 checks whether or not the sequence number <response confirmation number (S22).

If so, a processing request notification is issued to the handover execution unit 4 (S23), and the handover execution unit 4 executes a handover process (S24). When the handover process is completed, the handover execution unit 4 issues a process request notification to the DL control unit 24 (S25). Upon receiving this notification, the DL control unit 24 creates a packet having a notification window size of 1 or more (S26), and delivers it to the data analysis unit 27 (S27). The data analysis unit 27 delivers the packet to the transmission / reception unit 26 (S28), and the transmission / reception unit 26 transmits the packet to the communication partner terminal (S29).
(Embodiment 3)
For the mobile radio terminal in this case, for example, the CINR measurement unit 21, the handover determination unit 1, the handover execution condition storage unit 22, the reception response return determination unit 2, the reception response reception determination unit 3, and the handover The execution unit 4, the data analysis unit 27, the transmission / reception unit 26, the DL control unit 24, the UL control unit 25, and the application unit 42 are configured. Next, the operation of each component will be described along the flow of processing.

  1. The handover execution condition storage unit 22 holds information about the conditions for executing the handover process in advance. As a setting means, for example, the administrator may set by a command, or information may be set by regular or irregular notification from the BS 30 (see FIG. 2). Not specified). In this embodiment, for example, as shown in FIG. 4, when the CINR value becomes smaller than 20 dB, execution of the handover process is determined.

  Note that an MS to which the present invention is applied requires more time than a conventional MS to determine whether to execute a handover process until the actual handover process is executed (in order to wait for all received responses to be returned). . As a result, when the MS is moving at a high speed, the MS to which the present invention is applied as compared with the conventional MS may be disconnected from the BS between the execution decision of the handover process and the execution. Becomes higher. For this reason, it is necessary to consider that the threshold value for determining the execution of the handover process is set higher than in the prior art so that communication with the BS is not easily interrupted.

  2. The transmission / reception unit 26, the data analysis unit 27, the OS 41, and the application unit 42 perform data transmission / reception and reception response transmission / reception with a communication partner terminal at regular or irregular intervals in cooperation. The transmission / reception unit 26 acquires data and a reception response from the communication partner terminal from the network and passes them to the data analysis unit 27. The data analysis unit 27 performs internal processing (details will be described later), and further passes the acquired data and reception response to the OS 41. The OS 41 transfers the data to an appropriate application and clears the data retransmission timer for the reception response. For Up Link, processing is performed in the reverse flow to that of downlink processing.

  3. The data analysis unit 27 receives the transmission data from the OS 41 to the communication partner terminal in addition to the DL data reception number and the DL reception response return number counting process described in 3 of (Embodiment 1). The number of UL data transmissions is counted up. When a reception response from the communication partner terminal is received from the transmission / reception unit 26, the number of UL reception response receptions is counted up. In the present embodiment, for example, as shown in FIG. 8, the number of UL transmission data is 1000, the number of UL reception response returns is 1000, and all reception responses to the transmission data are received.

  4). The CINR measurement unit 21 calculates the CINR value by measuring the RSSI value and noise component of the BS 30 at regular or irregular intervals. In the present embodiment, for example, the calculated CINR value is 15 dB. The CINR measurement unit 21 notifies the handover determination unit 1 of the CINR value 15 dB.

  5. The handover determining unit 1 compares the CINR value 15 dB with the execution determination threshold 20 dB held in the handover execution condition storage unit 22. In this case, since the measured value is lower than the threshold value and satisfies the condition for executing the handover process, the handover determining unit 1 determines the execution of the handover process, and receives the processing request as a reception response return determination unit. 2. In addition to the DL control unit 24, the reception response reception determination unit 3 and the UL control unit 25 are notified. If the conditions for executing the handover process are not satisfied, the handover determining unit 1 does nothing.

  6). When the DL control unit 24 receives a processing request from the handover determining unit 1, the DL control unit 24 creates a packet in which the notification window size addressed to the communication partner terminal is 0, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and stop data transmission from the communication partner terminal.

  The sixth process is not an essential process in the present invention. However, when an MS to which the present invention is applied in a real environment executes a handover, if data is transmitted without interruption from the communication partner terminal, there is always a state in which an unreturned receiving terminal remains in the MS. Since there is a possibility that the handover process cannot be executed, it is necessary to consider that data transmission from the communication partner terminal is stopped by some method. In the present invention, the method is not specified, but there is a method of transmitting a packet with a notification window size of 0 as shown in the present embodiment to the communication partner.

  7). When receiving the processing request from the handover determining unit 1, the reception response return determination unit 2 refers to the DL data reception number and DL reception response reply number of the data analysis unit 27, and receives a response to the reception data from the communication partner terminal Check if all the items are returned. In the present embodiment, as shown in FIG. 8, since the DL data reception number and the DL reception response return number are the same, the reception response return determination unit 2 determines that all reception responses have been returned, and the handover execution unit 4 is notified of the processing request. If the DL data reception number is larger than the DL reception response return number, it is determined that there is an unreturned reception response and waits until all reception responses are returned.

  8). When receiving a processing request from the handover determining unit 1, the UL control unit 25 accumulates data received from the application unit 42 thereafter and stops data transmission (delivery to the data analyzing unit 27). This process is not an essential process in the present invention. However, when data is transmitted from the application unit 42 without interruption when the MS to which the present invention is applied in a real environment performs handover, the MS always has an unreturned reception response remaining. Since there is a possibility that the handover process cannot be executed, it is necessary to consider that data transmission is stopped by some method. In the present invention, the method is not specified, but there is a method of storing transmission data in the OS 41 as shown in the present embodiment, for example.

  9. When receiving a processing request from the handover determining unit 1, the reception response reception determination unit 3 refers to the UL data transmission number and the UL reception response reception number of the data analysis unit 27, and sends a reception response to the transmission data to the communication partner terminal. Check if everything is received. In the present embodiment, as shown in FIG. 8, since the number of UL data transmissions and the number of UL reception responses received are the same, the reception response reception determination unit 3 determines that all reception responses have been received, and the handover execution unit 4 is notified of the processing request. If the UL data transmission number is larger than the UL reception response reception number, it is determined that there is an unreceived reception response and waits until a reception response is received.

  10. When the handover execution unit 4 receives processing requests from the reception response return determination unit 2 and the reception response reception determination unit 3, the handover execution unit 4 executes a handover process. When the handover process is completed, the DL controller 24 and the UL controller 25 are notified of the processing request.

  11. Upon receiving a processing request from the handover execution unit 4, the DL control unit 24 creates a packet with a notification window size addressed to the communication partner terminal of 1 or more, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and resume data transmission from the communication partner terminal.

  12 When receiving a processing request from the handover execution unit 4, the UL control unit 25 cancels the accumulation of data received from the application unit 42, transfers the accumulated data to the data analysis unit 27, and resumes data transmission.

  According to this embodiment, since all reception responses are received from the communication partner terminal before the handover process is executed, it is possible to prevent the data retransmission timer of the mobile radio terminal from timing out during the handover process. It is possible to prevent a reduction in communication throughput after completion of the handover process by the start algorithm.

  11 and 12 are sequence diagrams showing an example of the operation of the present invention described above. When the transmission / reception unit 26 receives the data (S1), it passes the received data to the data analysis unit 27 (S2). The data analysis unit 27 counts the number of received data (S3). Then, the received data is transferred to the OS 41 (S4). The OS 41 delivers the received data to the application unit 42 (S5). Next, the OS 41 delivers a reception response to the data analysis unit 27 (S6). When receiving the reception response, the data analysis unit 27 counts the number of reception response returns (S7). Thereafter, the reception response is transferred to the transmission / reception unit 26 (S8), and the transmission / reception unit 26 transmits the reception response to the communication partner terminal (S9).

  On the other hand, the application unit 42 delivers the transmission data to the OS 41 (S10). The OS 41 delivers the transmission data to the data analysis unit 27 (S11). The data analysis unit 27 counts the number of transmission data (S12) and transfers it to the transmission / reception unit 26 (S13). The transmitting / receiving unit 26 transmits the transmission data to the communication partner terminal (S14). When a reception response to this data transmission is returned from the communication partner terminal, the transmission / reception unit 26 receives the reception response (S15). Then, the received reception response is transferred to the data analysis unit 27 (S16). The data analysis unit 27 receives the reception response, counts the number of reception responses received (S17), and passes the reception response to the OS 41 (S18).

  On the other hand, the CINR measurement unit 21 measures the CINR value (S19). The measurement result is notified to the handover determining unit 1 (S20). The handover determining unit 1 refers to the handover execution condition storage unit 22 (S21), and checks whether CINR measurement value <threshold value (S22). If so, the DL control unit 24 is notified of the processing request (S23). Upon receiving this processing request notification, the DL control unit 24 creates a packet with a notification window size of 0 (S24), and transfers it to the data analysis unit 27 (S25). The data analysis unit 27 delivers the packet to the transmission / reception unit 26 (S26). The transmitting / receiving unit 26 transmits the packet to the communication partner terminal (S27).

  If the CINR measurement value <threshold value, the handover determining unit 1 issues a processing request notification to the UL control unit 25 (S28). Upon receiving the processing request notification, the UL control unit 25 accumulates subsequent transmission data (S29). If CINR measurement value <threshold value, the handover determining unit 1 issues a processing request notification to the reception response return determining unit 2 (S30). Also, a processing request notification is sent to the reception response reception determination unit 3 (S31).

  Upon receiving this processing request, the reception response return determination unit 2 accesses the DL reception response confirmation number storage unit 8 and refers to the number of received data and the number of reception responses received (S32). Then, it is checked whether or not the number of transmission data = the number of response returns (S33). When receiving the processing request notification, the reception response reception determination unit 3 accesses the UL reception confirmation number storage unit 10 and refers to the transmission data number and the reception response reception number (S34). Then, it is checked whether or not the number of transmission data = the number of response receptions (S35).

  If the number of transmission data = the number of received responses, a processing request notification is issued to the handover execution unit 4 (S36). If the received data number is equal to the response return number, the reception response return determination unit 2 issues a processing request notification to the handover execution unit 4 (S37). Upon receiving these requests, the handover execution unit 4 executes a handover process (S38).

  When executing the handover process, the handover execution unit 4 notifies the UL control unit 25 of a processing request (S39). Upon receiving this notification, the UL control unit 25 cancels the accumulation of transmission data (S40), and transfers the accumulated data to the data analysis unit 27 (S41). The data analysis unit 27 delivers the transmission data to the transmission / reception unit 26 (S42). The transmitting / receiving unit 26 transmits transmission data to the communication partner terminal (S43).

Further, the handover execution unit 4 notifies the DL control unit 24 of a processing request (S44). Receiving the processing request notification, the DL control unit 24 creates a packet having a notification window size of 1 or more (S45), and delivers the packet to the data analysis unit 27 (S46). The data analysis unit 27 transfers the transferred packet to the transmission / reception unit 26 (S47). The transmitting / receiving unit transmits the packet to the communication partner terminal (S48).
(Embodiment 4)
For the mobile radio terminal (MS) in this case, for example, the CINR measurement unit 21, the handover determination unit 1, the handover execution condition storage unit 22, the reception response return determination unit 2, and the reception response reception determination unit 3 DL transmission sequence number storage unit 7, DL reception response confirmation number storage unit 8, UL transmission sequence number storage unit 9, UL reception response confirmation number storage unit 10, handover execution unit 4, data analysis The unit 27, the transmission / reception unit 26, the OS 41, the DL control unit 24, the UL control unit 25, and the application unit 42 are configured. Next, the operation of each component will be described along the flow of processing.

  1. The handover execution condition storage unit 22 holds information about the conditions for executing the handover process in advance. As a setting means, for example, the administrator may set by a command, or information may be set by regular or irregular notification from the BS 30 (see FIG. 2). Not specified). In this embodiment, for example, as shown in FIG. 4, when the CINR value becomes smaller than 20 dB, execution of the handover process is determined.

  Note that an MS to which the present invention is applied requires more time than a conventional MS to determine whether to execute a handover process until the actual handover process is executed (in order to wait for all received responses to be returned). . As a result, when the MS is moving at a high speed, the MS to which the present invention is applied as compared with the conventional MS may be disconnected from the BS between the execution decision of the handover process and the execution. Becomes higher. For this reason, it is necessary to consider that the threshold value for determining the execution of the handover process is set higher than in the prior art so that communication with the BS is not easily interrupted.

  2. The transmission / reception unit 26, the data analysis unit 27, the OS 41, and the application unit 42 perform data transmission / reception and reception response transmission / reception with a communication partner terminal at regular or irregular intervals in cooperation. The transmission / reception unit 26 acquires data and a reception response from the communication partner terminal from the network and passes them to the data analysis unit 27. The data analysis unit 27 performs internal processing (details will be described later), and further passes the acquired data and reception response to the OS 41. The OS 41 transfers the data to an appropriate application and clears the data retransmission timer for the reception response. For Up Link, processing is performed in the reverse flow to that of downlink processing.

  3. The data analysis unit 27 holds the transmission sequence number of the received data and the reception response confirmation number of the received reception response described in 3 of (Embodiment 2), as well as the transmission data to the communication partner terminal. When received from the OS 41, the data packet is analyzed, the TCP sequence transmission sequence number is acquired, and held in the UL transmission sequence number storage unit 7.

  When a reception response transmitted from the communication partner terminal is received from the transmission / reception unit 26, the reception response packet is analyzed, a TCP layer response confirmation number is acquired, and held in the UL reception response confirmation number storage unit 10. In the present embodiment, as shown in FIG. 6, for example, it is assumed that the UL transmission sequence number is 500, the UL reception response confirmation number is 500, and the MS has a reception response that has not been received.

  4). The CINR measurement unit 21 calculates the CINR value by measuring the RSSI value and noise component of the BS 30 at regular or irregular intervals. In the present embodiment, for example, the calculated CINR value is 15 dB. The CINR measurement unit 21 notifies the handover determination unit 1 of the CINR value 15 dB.

  5. The handover determining unit 1 compares the CINR value 15 dB with the execution determination threshold 20 dB held in the handover execution condition storage unit 22. In this case, since the measured value is lower than the threshold value and satisfies the condition for executing the handover process, the handover determining unit 1 determines the execution of the handover process, and receives the processing request as a reception response return determination unit. 2. In addition to the DL control unit 24, the reception response reception determination unit 3 and the UL control unit 25 are also notified. If the conditions for executing the handover process are not satisfied, the handover determining unit 1 does nothing.

  6). When the DL control unit 24 receives a processing request from the handover determining unit 1, the DL control unit 24 creates a packet in which the notification window size addressed to the communication partner terminal is 0, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and stop data transmission from the communication partner terminal.

  The sixth process is not an essential process in the present invention. However, when an MS to which the present invention is applied in a real environment executes a handover, if data is transmitted without interruption from the communication partner terminal, there is always a state in which an unreturned receiving terminal remains in the MS. Since there is a possibility that the handover process cannot be executed, it is necessary to consider that data transmission from the communication partner terminal is stopped by some method. In the present invention, the method is not specified, but there is a method of transmitting a packet with a notification window size of 0 as shown in the present embodiment to the communication partner.

  7). When receiving the processing request from the handover determining unit 1, the reception response return determination unit 2 refers to the DL data reception number and DL reception response reply number of the data analysis unit 27, and receives a response to the reception data from the communication partner terminal Check if all the items are returned. In the present embodiment, as shown in FIG. 8, since the DL data reception number and the DL reception response return number are the same, the reception response return determination unit 2 determines that all reception responses have been returned, and the handover execution unit 4 is notified of the processing request. If the DL data reception number is larger than the DL reception response return number, it is determined that there is an unreturned reception response and waits until all reception responses are returned.

  8). When receiving a processing request from the handover determining unit 1, the UL control unit 25 accumulates data received from the application unit 42 thereafter and stops data transmission (delivery to the data analyzing unit 27). This process is not an essential process in the present invention. However, when data is transmitted from the application unit 42 without interruption when the MS to which the present invention is applied in a real environment performs handover, the MS always has an unreturned reception response remaining. Since there is a possibility that the handover process cannot be executed, it is necessary to consider that data transmission is stopped by some method.

9. When receiving the processing request from the handover determining unit 1, the reception response reception determining unit 3 receives the UL reception transmission sequence number and the UL reception response from the UL transmission sequence number storage unit 9 and the UL reception response confirmation number storage unit 10, respectively. Get confirmation numbers and compare. In the example of FIG. 6 of the present embodiment, since these values are the same value, the reception response reception determination unit 3 determines that there is still a reception response that has not been received by the MS, and receives the reception response. Wait until. Thereafter, the UL transmission sequence number and the UL reception response confirmation number are monitored regularly or irregularly, and the relationship between the transmission sequence number and the reception response confirmation number is
When the transmission sequence number <the reception response confirmation number, the reception response reception determination unit 3 determines that all reception responses have been received, and notifies the handover execution unit 4 of the processing request.

  10. When the handover execution unit 4 receives processing requests from the reception response return determination unit 2 and the reception response reception determination unit 3, the handover execution unit 4 executes a handover process. When the handover process is completed, the DL controller 24 and the UL controller 25 are notified of the processing request.

  11. Upon receiving a processing request from the handover execution unit 4, the DL control unit 24 creates a packet with a notification window size addressed to the communication partner terminal of 1 or more, and delivers the packet to the data analysis unit 27. The data analysis unit 27 and the transmission / reception unit 26 cooperate to transmit the packet to the communication partner terminal, and resume data transmission from the communication partner terminal.

  12 When receiving a processing request from the handover execution unit 4, the UL control unit 25 cancels the accumulation of data received from the application unit 42, transfers the accumulated data to the data analysis unit 27, and resumes data transmission.

According to this embodiment, even when one reception response corresponds to the reception response of a plurality of transmission data, it is possible to accurately grasp the reception state of the reception response.
13 and 14 are diagrams showing an example of the operation of the above-described embodiment. When the transmission / reception unit 26 receives the data (S1), it passes the received data to the data analysis unit 27 (S2). The data analysis unit 27 stores the sequence number of the received data in the DL transmission sequence number storage unit 7 (S3). At the same time, the data analysis unit 27 delivers the received data to the OS 41 (S4). The OS 41 delivers the received data to the application unit 42 (S5). The OS 41 passes the reception response to the data analysis unit 27 (S6). The data analysis unit 27 stores the response confirmation number in the DL reception response confirmation number storage unit 8 (S7). At the same time, the data analysis unit 27 passes the reception response to the transmission / reception unit 26 (S8), and the transmission / reception unit 26 transmits the reception response to the communication partner terminal (S9).

  On the other hand, the application unit 42 delivers transmission data to the OS 41 (S10), and the OS 41 delivers transmission data to the data analysis unit 27 (S11). The data analysis unit 27 stores the sequence number in the UL transmission sequence number storage unit 9 (S12), and transfers the transmission data to the transmission / reception unit 26 (S13). The transmitting / receiving unit 26 transmits the transmission data to the communication partner terminal (S14).

  When the transmission / reception unit 26 receives a reception response from the communication counterpart terminal (S15), the transmission / reception unit 26 passes the reception response to the data analysis unit 27 (S16). The data analysis unit 27 stores the response confirmation number in the UL reception response confirmation number storage unit 10 (S17), and transfers the reception response to the OS 41 (S18).

  On the other hand, the CINR measurement unit 21 measures the CINR value (S19), and notifies the handover determination unit 1 of the measurement value (S20). The handover determining unit 1 accesses the handover execution condition storage unit 22, reads the condition data (S21), and checks whether CINR measurement value <threshold value (S22). If so, a processing request notification is sent to the DL control unit 24 (S23). Upon receiving this notification, the DL control unit 24 creates a packet with a notification window size of 0 (S24), and delivers the packet to the data analysis unit 27 (S25). The data analysis unit 27 transfers this packet to the transmission / reception unit 26 (S26). The transmitting / receiving unit 26 transmits the packet to the communication partner terminal (S27).

  In step S22, when CINR measurement value <threshold value, the handover determining unit 1 notifies the UL control unit 25 of a processing request (S28). The UL control unit 25 accumulates subsequent transmission data (S29).

  The handover determining unit 1 notifies the reception response / return determination unit 2 of the processing request (S30) and notifies the reception response reception determination unit 3 of the processing request (S31). The reception response return determination unit 2 accesses the DL reception response confirmation number storage unit 8 to refer to the response confirmation number (S32), and accesses the DL transmission sequence number storage unit 7 to refer to the transmission sequence number ( S33). Then, it is checked whether sequence number <response confirmation number based on the referred result (S34).

  The reception response reception determination unit 3 accesses the UL reception response confirmation number storage unit 10 to refer to the response confirmation number (S35), and accesses the UL transmission sequence number storage unit 9 to refer to the transmission sequence number. (S36). Then, it is checked whether sequence number <response confirmation number (S37). If so, a processing request notification is sent to the handover execution unit 4 (S38). In step S34, if the sequence number is smaller than the response confirmation number, the handover execution unit 4 is notified of the processing request (S39).

  When the handover execution unit 4 executes the handover (S40), the handover execution unit 4 sends a processing request notification to the UL control unit 25 (S41). Upon receiving this notification, the UL control unit 25 cancels the accumulation of transmission data (S42), and transfers the accumulated data to the data analysis unit 27 (S43). The data analysis unit 27 delivers the transmission data to the transmission / reception unit 26 (S44), and the transmission / reception unit 26 transmits data to the communication partner terminal (S45).

The handover execution unit 4 also sends a processing request notification to the DL control unit 24 (S46). The DL control unit 24 creates a packet having a notification window size of 1 or more (S47), and transfers the packet to the data analysis unit 27 (S48). The data analysis unit 27 delivers the packet to the transmission / reception unit 26 (S49), and the transmission / reception unit 26 transfers the packet to the communication partner terminal (S50).
(Embodiment 5)
For the mobile communication terminal in this case, for example, the CINR measurement unit 21, the handover determination unit 1, the handover execution condition storage unit 22, the handover forced execution condition storage unit 23, the reception response return determination unit 2, Reception response reception determination unit 3, DL transmission sequence number storage unit 7, DL reception response confirmation number storage unit 8, UL transmission sequence number storage unit 9, UL reception response confirmation number storage unit 10, handover The execution unit 4, the data analysis unit 27, the transmission / reception unit 26, the OS 41, and the application unit 42 are configured. Next, the operation of each component will be described along the flow of processing.

  1. This embodiment is the same as 1 to 12 in (Embodiment 4). However, in 1 and 2 in (Embodiment 4), the handover forcible execution condition storage unit 23 pre-loads handover processing. Stores information about execution conditions. As a setting means, for example, the administrator may set by a command, or information may be set by regular or irregular notification from the BS (this means is not specified in the present invention). In this embodiment, for example, as shown in FIG. 4, when the CINR value of the BS becomes smaller than 12.5 dB, the forced execution of the handover process is determined.

  2. In (Embodiment 4) 4 and 5, the handover determining unit 1 receives the CINR value from the CINR measuring unit 21 even after determining the execution of the handover process, and determines the forced execution of the handover process. In the present embodiment, for example, it is assumed that the CINR value of the BS is 12 dB. The handover determining unit 1 compares the CINR value of 12 dB with the forced execution determination threshold value 12.5 dB held in the handover forced execution condition storage unit 23. Since the measured value is lower than the threshold value and satisfies the forced execution condition of the handover process, the handover determination unit 1 determines the forced execution of the handover process and notifies the handover execution unit 4 of the processing request. .

3. Same as 10-12 in (Embodiment 3).
According to this embodiment, even if the mobile radio terminal is in a state of receiving or returning a reception response, the handover process can be executed if the condition for forced execution is satisfied, and the reception or reception of a reception response is awaited. It is possible to avoid a situation in which communication with the radio base station is interrupted in this state.

  15 and 16 are diagrams showing an example of the operation of the above-described embodiment. When the transmission / reception unit 26 receives data from the communication partner terminal (S1), the transmission / reception unit 26 transfers the data to the data analysis unit 27 (S2). The data analysis unit 27 stores the sequence number of the data in the DL transmission sequence number storage unit 7 (S3). Then, the data analysis unit 27 delivers the received data to the OS 41 (S4). The OS 41 delivers the received data to the application unit 42 (S5). Next, the OS 41 passes the reception response to the data analysis unit 27 (S6). The data analysis unit 27 stores the response number in the DL reception response confirmation number storage unit 8 (S7), and passes the reception response to the transmission / reception unit 26 (S8). The transmitting / receiving unit 26 transmits a reception response to the communication partner terminal (S9).

  On the other hand, the application unit 42 delivers the transmission data to the OS 41 (S10). The OS 41 delivers the transmission data to the data analysis unit 27 (S11). The data analysis unit 27 stores the sequence number of the transmission data in the UL transmission sequence number storage unit 9 (S12), and then transfers the transmission data to the transmission / reception unit 26 (S13). The transmitting / receiving unit 26 transmits the transmission data to the communication partner terminal (S14).

  In addition, when the transmission / reception unit 26 receives a reception response from the communication partner terminal (S15), the transmission / reception unit 26 passes this reception response to the data analysis unit 27 (S16). The data analysis unit 27 stores the response confirmation number in the UL reception response confirmation number storage unit 10 (S17), and then transfers the reception response to the OS 41 (S18).

  On the other hand, the CINR measurement unit 21 measures CINR (S19). Then, the measurement result is notified to the handover determining unit 1 (S20). The handover determining unit 1 refers to the handover execution condition storage unit 22 (S21) and checks whether CINR measurement value <threshold value (S22). If so, the handover determining unit 1 sends a processing request notification to the DL control unit 24 (S23). Upon receiving this processing request notification, the DL control unit 24 creates a packet with a notification window size of 0 (S24) and transfers it to the data analysis unit 27 (S25). The data analysis unit 27 delivers the packet to the transmission / reception unit 26 (S26). The transmitting / receiving unit 26 transmits the packet to the communication partner terminal (S27).

  When the measured value <threshold value, the handover determining unit 1 notifies the UL control unit 25 of a processing request (S28). Upon receiving this notification, the UL control unit 25 accumulates subsequent transmission data (S29). The handover determining unit 1 notifies the reception response / return determining unit 2 of the processing request (S30). Further, the handover determining unit 1 makes a processing request to the reception response reception determining unit 3 (S31).

  On the other hand, the CINR measurement unit 21 measures the intensity (CINR) of radio waves (S32). Then, the measurement result is notified to the handover determining unit 1 (S33). The handover determining unit 1 accesses the handover execution condition storage unit 22 and refers to the execution condition (S34). Then, it is checked whether measured value <threshold value (S35). If so, the handover execution unit 4 is notified of the processing request (S36). The handover execution unit 4 performs a handover process (S37). After executing the handover process, the handover execution unit 4 notifies the UL control unit 25 of a processing request (S38). Receiving this processing request notification, the UL control unit 25 cancels the accumulation of transmission data (S39), and transfers the accumulated data to the data analysis unit 27 (S40). The data analysis unit 27 transfers the received accumulated data to the transmission / reception unit 26 as transmission data (S41). The transmitting / receiving unit 26 transmits the transmission data to the communication partner terminal (S42).

  In addition, the handover execution unit 4 notifies the DL control unit 24 of a processing request after finishing the handover process (S43). Upon receiving this notification, the DL control unit 24 creates a packet having a notification window size of 1 or more (S44), and delivers it to the data analysis unit 27 (S45). The data analysis unit 27 delivers the packet to the transmission / reception unit 26 (S46). The transmitting / receiving unit 26 transmits the transferred packet to the communication partner terminal (S47).

(Appendix 1)
A mobile radio terminal and a plurality of radio base stations that communicate with the mobile radio terminal by radio, the communication between the mobile radio terminal and its counterpart terminal could not receive a reception response to transmission data within a certain period of time A mobile radio terminal in a radio communication system for controlling to reduce the communication speed between the mobile radio terminal and the communication counterpart terminal,
In response to a request from the radio base station, or autonomously determining handover execution to another radio base station, handover determining means;
A reception response return determination means for checking whether or not the return of all reception responses is completed when execution of the handover process is determined by the handover determination means;
When it is determined by the reception response return determination means that the reception response has been returned, a handover execution means for executing the handover process;
A mobile radio terminal in a radio communication system comprising:

(Appendix 2)
DL reception response confirmation number storage unit for storing a response confirmation number of a reception response last transmitted to the communication partner terminal by the reception response return determination unit; and a transmission sequence number of transmission data last received from the communication partner terminal A DL transmission sequence number storage unit for storing
Judging that the reception response has been returned by comparing the response confirmation number stored in the DL reception response confirmation number storage unit with the transmission sequence number stored in the DL transmission sequence number storage unit A mobile radio terminal in the radio communication system according to appendix 1.

(Appendix 3)
When the mobile radio terminal is determined by the handover determining means to execute the handover process, the mobile radio terminal comprises reception response reception determination means for checking whether or not reception of all reception responses has been completed,
The mobile radio terminal in the radio communication system according to appendix 1 or 2, wherein the handover process is executed when reception of the reception response is determined by the reception response reception determination means.

(Appendix 4)
A mobile radio terminal and a plurality of radio base stations that communicate with the mobile radio terminal by radio, the communication between the mobile radio terminal and its counterpart terminal could not receive a reception response to transmission data within a certain period of time In the case of a wireless communication system that controls to reduce the communication speed between the mobile wireless terminal and the communication counterpart terminal,
When the mobile radio terminal decides to execute a handover process to another radio base station in response to a request from the radio base station or autonomously, whether or not all reception responses have been returned to the communication counterpart terminal A handover processing apparatus in a wireless communication system, wherein the handover process is executed when it is determined that all reception responses have been returned. (Appendix 5)
Whether or not all the reception responses have been returned by comparing the transmission sequence number of the transmission data last received by the mobile radio terminal from the communication partner terminal with the response confirmation number of the reception response last returned to the communication partner terminal The handover processing apparatus in the wireless communication system according to claim 4, wherein:

(Appendix 6)
If the mobile radio terminal determines to execute a handover process to another radio base station in response to a request from the radio base station or autonomously, whether or not all reception responses have been received from the communication counterpart terminal The handover processing device in the wireless communication system according to appendix 4 or 5, wherein the handover process is executed when it is determined that all reception responses have been received.

(Appendix 7)
Whether or not all reception responses have been received by comparing the transmission sequence number of the transmission data last transmitted by the mobile radio terminal to the communication partner terminal and the response confirmation number of the reception response last received from the communication counterpart terminal The handover processing device in the wireless communication system according to supplementary note 6, characterized by:

(Appendix 8)
After the mobile radio terminal decides to execute the handover process, the condition information for the forced execution of the handover process is monitored, and if the conditions for the forced execution are satisfied, all of the reception responses are returned before returning all of the reception responses. 8. A handover processing apparatus in a wireless communication system according to any one of appendices 4 to 7, wherein the handover processing is forcibly executed even before reception.

(Appendix 9)
The reception response reception determination unit stores a UL response confirmation number storage unit that stores a response confirmation number of the last received response received from the communication partner terminal, and stores a transmission sequence number of transmission data that was last transmitted to the communication partner terminal. A UL transmission sequence number storage unit
It is determined that reception of a reception response is completed by comparing a response confirmation number stored in the UL response confirmation number storage unit with a transmission sequence number stored in the UL transmission sequence number storage unit. A mobile radio terminal in the radio communication system according to appendix 3.

(Appendix 10)
A forced execution condition storage unit that stores information on the forced execution condition of the handover process by the mobile radio terminal, and a handover forcible determination that determines the forced execution of the handover process based on the information in the forced execution condition storage unit An execution decision unit,
The wireless communication system according to any one of appendices 1 to 3 and 9, wherein when the handover forcible execution determination unit determines to forcibly execute the handover processing, the handover processing is executed. Mobile radio terminal.

  As described above in detail, in the present invention, it is determined whether or not all reception responses have been returned in response to the received data from the communication partner in response to the execution of the handover being determined. By executing the handover process after returning the response, there is an effect that the reception response does not stay in the mobile radio terminal during the handover process, and as a result, after the handover process by the slow start algorithm is completed. It is possible to prevent a reduction in communication throughput and contribute to improving the performance of the wireless communication system.

It is a principle block diagram of the present invention. It is a figure which shows the system configuration example to which this invention is applied. It is a block diagram which shows one Embodiment of the mobile radio | wireless terminal in this invention. It is a figure which shows an example of a handover execution condition storage part. It is a figure which shows an example of a hand-over forced execution condition storage part. It is a figure which shows an example of a DL transmission sequence number storage part and a response confirmation number storage part for DL reception. It is a figure which shows an example of the UL transmission sequence number storage part and the response confirmation number storage part for UL reception. It is a figure which shows an example of the data transmission / reception number in a data analysis part, and a reception response transmission / reception number. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention. It is a sequence diagram which shows an example of operation | movement of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Handover determination part 2 Reception response return determination part 3 Reception response reception determination part 4 Handover execution part 7 DL transmission sequence number storage part 8 DL reception response confirmation number storage part 9 UL transmission sequence number storage part 10 UL reception response Confirmation number storage unit 21 CINR measurement unit 22 Handover execution condition storage unit 23 Handover forced execution condition storage unit 24 DL control unit 25 UL control unit 25
26 Transmission / Reception Unit 27 Data Analysis Unit 41 Operating System (OS)
42 Application Department

Claims (5)

A mobile radio terminal and a plurality of radio base stations that communicate with the mobile radio terminal by radio, the communication between the mobile radio terminal and its counterpart terminal could not receive a reception response to transmission data within a certain period of time A mobile radio terminal in a radio communication system for controlling to reduce the communication speed between the mobile radio terminal and the communication counterpart terminal,
In response to a request from the radio base station, or autonomously determining handover execution to another radio base station, handover determining means;
When it is determined that the handover process is executed by the handover determination unit, a reception response return determination unit that checks whether or not all reception responses for the data received from the communication counterpart terminals are returned ,
When it is determined by the reception response return determination means that the reception response has been returned, a handover execution means for executing the handover process;
A mobile radio terminal in a radio communication system comprising: DL reception response confirmation number storage unit for storing a response confirmation number of a reception response last transmitted to the communication partner terminal by the reception response return determination unit; and a transmission sequence number of transmission data last received from the communication partner terminal A DL transmission sequence number storage unit for storing
Judging that the reception response has been returned by comparing the response confirmation number stored in the DL reception response confirmation number storage unit with the transmission sequence number stored in the DL transmission sequence number storage unit The mobile radio terminal in the radio communication system according to claim 1. When the mobile radio terminal determines execution of the handover process by the handover determining means, a reception response reception is performed to check whether or not all reception responses for each data transmitted to the communication counterpart terminal have been received. A determination means,
3. The mobile radio terminal in the radio communication system according to claim 1, wherein when the reception response reception determination unit determines that reception of the reception response is completed, the handover process is executed. A mobile radio terminal and a plurality of radio base stations that communicate with the mobile radio terminal by radio,
A wireless communication system for controlling the communication speed between the mobile wireless terminal and the communication partner terminal to be lowered when a reception response to the transmission data is not received within a certain time in communication between the mobile wireless terminal and the communication partner terminal In
When the mobile radio terminal determines to execute a handover process to another radio base station in response to a request from the radio base station or autonomously, a reception response for each of the data received from the communication counterpart terminal, A handover processing apparatus in a radio communication system, characterized in that it judges whether or not all transmissions have been transmitted to the communication partner terminal, and executes the handover process when it is judged that all reception responses have been transmitted .   Whether or not all the reception responses have been returned by comparing the transmission sequence number of the transmission data last received by the mobile radio terminal from the communication partner terminal with the response confirmation number of the reception response last returned to the communication partner terminal The handover processing apparatus in the wireless communication system according to claim 4, wherein:

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